Is XLR always louder than 1/4" out?

[boltrecords]

Im noticing a difference in volume between when I use XLR out Left vs the 1/4" out Left. Is this always the case when using balanced vs unbalanced?

 

[Rex]

Yes. All other things being equal, there is a 6 dB difference between balanced and unbalanced signals.


Let's say you have a 1-volt unbalanced signal. That's 1 volt working against ground (0 volts), for a total of 1 volt.

With a balanced signal, there's the original 1 volt signal, plus an out-of-phase signal at -1 volts. The difference between +1 and -1 is 2 volts. That's twice the voltage, which equals four times the power, which equals a 6 dB difference.

 

[Rumbletone]

Specially which outputs are you referring to (for example, per the manual out1 and out3 1/4" outputs have different output levels, by design ...) and what are you plugging them into?

For out1 the XLR and 1/4 outputs are identical, according to the manual (so the level is the same) - so if you're getting a difference in volume between those you have a cabling issue. [edit - per below, they are 'the same' but not the same (i.e., not the same level)]

And the cable itself shouldn't affect the volume per se, but - for example - plugging a balanced output into an unbalanced input will cause a volume drop.

Also, note that the 1/4" outputs are not unbalanced - they are all balanced (according to the manual). So if you're plugging the 1/4" output into a balanced 1/4" input (or, for that matter, a balanced XLR input ...) I would recommend using a TRS cable. [edit: per below, the 1/4" outputs are unbalanced] If you connect the balanced 1/4" output of the FM9 to a balanced input but use a TS (regular instrument) cable, you are not making a balanced connection and will lose the benefit of balanced outputs (reduced risk of noise) and will have a volume drop.

 

[Rex]

For out1 the XLR and 1/4 outputs are identical, according to the manual (so the level is the same) - so if you're getting a difference in volume between those you have a cabling issue.

Both XLR and 1/4” outputs are fed identical signals, but they have different levels. A balanced signal is, by nature, 6 dB hotter than an identical unbalanced signal.

Also, note that the 1/4" outputs are not unbalanced - they are all balanced (according to the manual).

The 1/4” outputs are unbalanced. If you tell us where in the manual it says otherwise, I’ll report the error.

 

[chris]

1/4” outputs are unbalanced. They have a TRS structure for Humbuster, but TRS itself doesn’t mean balanced.

 

[Rumbletone]

Both XLR and 1/4” outputs are fed identical signals, but they have different levels. A balanced signal is, by nature, 6 dB hotter than an identical unbalanced signal.


The 1/4” outputs are unbalanced. If you tell us where in the manual it says otherwise, I’ll report the error.

I was looking at page 21 - which clearly says that the 1/4" are unbalanced! I must have been looking at the inputs! Apologies - will correct above ...

 

[Rex]

I was looking at page 21 - which clearly says that the 1/4" are unbalanced! I must have been looking at the inputs! Apologies - will correct above ...

No worries. Shit happens — and sometimes I'm the one taking the dump.

 

[Rumbletone]

A balanced signal is, by nature, 6 dB hotter than an identical unbalanced signal.

My understanding - which is, admittedly, limited! (I am not an EE ..) - is that it would be true of a differential signal on a balanced line, and where the unbalanced signal is created by taking just one side of the differential signal and connecting the other to ground. But my understanding is that a balanced line need not necessarily be carrying a differential signal, and many devices have balanced and unbalanced outputs that are not created merely by connecting only half of the balanced output - for example, if the unbalanced output is created via transformer, can't it be done without a drop (like in the below)?

Asking in part because I'm thinking of building an interface for a live rig that, among other things, converts between balanced and unbalanced, and am trying to understand the best way to do it ...

 

[Rumbletone]

No worries. Shit happens — and sometimes I'm the one taking the dump.

The irony is that I thought they were unbalanced, but decided that I should check the manual first to be sure and was surprised to (incorrectly) read that they weren't!!

 

[Rex]

My understanding - which is, admittedly, limited! (I am not an EE ..) - is that it would be true of a differential signal on a balanced line, and where the unbalanced signal is created by taking just one side of the differential signal and connecting the other to ground. But my understanding is that a balanced line need not necessarily be carrying a differential signal, and many devices have balanced and unbalanced outputs that are not created merely by connecting only half of the balanced output - for example, if the unbalanced output is created via transformer, can't it be done without a drop (like in the below)?

Asking in part because I'm thinking of building an interface for a live rig that, among other things, converts between balanced and unbalanced, and am trying to understand the best way to do it ...

View attachment 108178

You're right. If you use a transformer to convert from balanced to unbalanced, you'll get pretty much the same signal level on both ends. That's how they make baluns, which are external devices for doing just that.

But transformers are expensive, and getting a transformer to give a flat response across the audio spectrum is really expensive. That's why you don't see transformers in most gear. Transformers are for those situations where you need the circuit isolation that they provide, or when you need to create a balanced signal from an unbalanced one. Instead,the circuit is designed to create a balanced signal, and the unbalanced signal is derived from just one side of the balanced pair.